The Vision Center is the Teacher.
You need to place your back foot and form your stance so your
personal vision center ends up above the desired line of the shot. And for a center-ball hit, the cue should also be along this line.
Now, once one knows what foot position and stance results in the most consistent and accurate vision center and cue alignments, then the foot placement becomes the key.
And if its not a center ball hit than what do you recommend to do. Where should the cue be?
... wherever it needs to be to
compensate for squirt, swerve, and throw for that particular shot.
Why would you compensate for these things?
... because these things are a reality when using sidespin. If one does not have either an intuitive or explicit understanding of
squirt, swerve, and throw effects, one will not be accurate and consistent over a wide range of shots involving sidespin.
Now, most top players like yourself who have put in countless hours of practice and have countless hours of successful experience probably do this so naturally that it is subconscious (although, even pros aren't perfect when it comes to compensating for squirt, swerve, and throw). But for those who have not put in enough time to intuitively or subconsciously judge how to compensate over a wide range of shots, it can help to have a solid understanding of the
effects. Also, IMO, this understanding can help speed the experience-based learning and intuition-building process.
This presents some serious problems and turns the contest into a "guessing game".
... it is only a "guessing game" if one doesn't understand and/or have an intuitive (and/or subconscious) feel for the important
effects.
How do you compensate, at the cue ball, object ball, or in relationship to the pocket?
I compensate for throw at the OB (relative to the pocket), and I compensate for the combined effects of squirt and swerve (AKA "net CB deflection") at the CB (with my cue alignment relative to the desired line of the shot). How this is done is covered in detail in the
"How to Aim Pool Shots" (HAPS) series. For the basics covering one method to adjust for net CB deflection, see:
NV E.2 - Back-Hand (BHE) and Front-Hand English (FHE), from HAPS I
Again, a top player like you doesn't need something like this because you have learned to do an equivalent version of this through your countless hours of play and experience. For the mere mortals out there who don't have the time, desire, or dedication to put in the countless hours, it can help to have some understanding and/or aim compensation "systems."
Regards with respect,
Dave